System and method for validating adaptive cruise control operations

ABSTRACT

A method of operating a vehicle comprising an adaptive cruise control system and an engine control module is provided. The engine control module is coupled to the adaptive cruise control system. The method comprises issuing a speed reduction signal from the adaptive cruise control system, verifying a speed reduction with a first sensor using the adaptive cruise control system, verifying the speed reduction with a second sensor using the engine control module, thereafter, receiving a resume signal from an operator input device, and executing a speed increase of the vehicle with the engine control module in response to receiving the resume signal with the engine control module.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally tocruise control systems for vehicles. More particularly, embodiments ofthe subject matter relate to systems and methods for validatingoperations and user input to adaptive cruise control systems.

BACKGROUND

Cruise control systems for vehicles have been widely used for convenienttravel. Adaptive cruise control systems (ACCSs) improve some featuresover standard systems, such as adjusting the speed of the vehicle inresponse to changing traffic conditions. For example, a vehicle underthe operation of an ACCS can monitor surrounding areas usingrange-finding techniques. Should the vehicle encounter a slow-movingvehicle in its lane, the ACCS can reduce the speed of the vehicle toprevent a collision, while continuing to operate the vehicle.Traditional cruise control systems would require the operator todisengage the cruise control system and resume manual operation of thevehicle.

Under certain driving conditions, an ACCS can bring the vehicle to acomplete stop. When a complete stop occurs, it can be difficult for theACCS to determine the circumstances of the stop. A complete stop couldresult from congested traffic, after which resumption of speed at a safefollowing distance would be an appropriate action for the system toundertake. A complete stop could also occur behind another vehicle at astop sign. When the preceding vehicle advances through the intersection,the way would be clear for the vehicle to resume its cruising speed,which would be an undesirable result. Accordingly, a conventional ACCSis unable to operate the vehicle properly from a stop.

Additionally, an ACCS typically interacts with an electronic enginecontroller. Owing to the multiply-connected nature of the ACCS, withcouplings to a variety of sensors and inputs, it is possible that theACCS will reach a state wherein it has an incorrect record of thecurrent operational state of the vehicle. For example, the ACCS couldhave received an incorrect signal indicating the vehicle is stopped froman improperly-functioning sensor, when in fact the vehicle is stillmoving. Thus, a conventional ACCS could transmit an inappropriatecommand signal following an incorrect sensor reading.

BRIEF SUMMARY

A method of operating a vehicle comprising an adaptive cruise controlsystem and an engine control module is provided. The engine controlmodule is coupled to the adaptive cruise control system. The methodcomprises issuing a speed reduction signal from the adaptive cruisecontrol system, verifying a speed reduction with a first sensor usingthe adaptive cruise control system, verifying the speed reduction with asecond sensor using the engine control module, thereafter, receiving aresume signal from an operator input device, and executing a speedincrease of the vehicle with the engine control module in response toreceiving the resume signal with the engine control module.

Another method of operating a vehicle comprising an adaptive cruisecontrol system and an engine control module is provided. The enginecontrol module is coupled to the adaptive cruise control system. Themethod comprises receiving a resume signal at the engine control module,the engine control module relaying the resume signal as a relayed resumesignal to the adaptive cruise control system, receiving a speed increasesignal at the engine control module, and executing a speed increase ofthe vehicle with the engine control module in response to the resumesignal and the speed increase signal.

A vehicular control system is also provided. The system comprises anadaptive cruise control system and an engine control module. Theadaptive cruise control system is adapted to engage an adaptive cruisecontrol mode in response to receiving an engagement signal from anoperator of the vehicle, transmit a speed reduction signal during theadaptive cruise control mode, verify speed reduction of the vehicleusing a first sensor, the speed reduction of the vehicle beinginfluenced by the speed reduction signal, receive a resume signal fromthe operator during the adaptive cruise control mode, and transmit aspeed increase signal in response to receiving the resume signal. Theengine control module is coupled to the adaptive cruise control systemand adapted to receive the speed reduction signal, execute the speedreduction in response to receiving the speed reduction signal, verifythe speed reduction using a second sensor, receive the resume signal,and execute a speed increase of the engine in response to receiving theresume signal and the speed increase signal.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the subject matter may be derived byreferring to the detailed description and claims when considered inconjunction with the following figures, wherein like reference numbersrefer to similar elements throughout the figures.

FIG. 1 is a schematic illustration of a vehicle with an adaptive cruisecontrol system;

FIG. 2 is a diagram showing a vehicle operated by an adaptive cruisecontrol system in a first state;

FIG. 3 is a diagram showing the vehicle of FIG. 2 in a second state; and

FIG. 4 is a schematic illustration of a method of operating a vehicleusing an adaptive cruise control system.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description.

Techniques and technologies may be described herein in terms offunctional components, and with reference to symbolic representations ofoperations, processing tasks, and functions. In practice, one or moreprocessor-driven devices can carry out the described operations, tasks,and functions. It should be appreciated that the various blockcomponents shown in the figures may be realized by any number ofhardware, software, and/or firmware components configured to perform thespecified functions. For example, an embodiment of a system or acomponent may employ various integrated circuit components which maycarry out a variety of functions under the control of one or moremicroprocessors or other control devices.

“Coupled”—The following description refers to elements or nodes orfeatures being “coupled” together. As used herein, unless expresslystated otherwise, “coupled” means that one element/node/feature isdirectly or indirectly joined to (or directly or indirectly communicateswith) another element/node/feature, and not necessarily mechanically.Thus, although the schematic shown in FIG. 1 depicts one exemplaryarrangement of elements, additional intervening elements, devices,features, or components may be present in an embodiment of the depictedsubject matter.

“Adjust”—Some elements, components, and/or features are described asbeing adjustable or adjusted. As used herein, unless expressly statedotherwise, “adjust” means to position, modify, alter, or dispose anelement or component or portion thereof as suitable to the circumstanceand embodiment. In certain cases, the element or component, or portionthereof, can remain in an unchanged position, state, and/or condition asa result of adjustment, if appropriate or desirable for the embodimentunder the circumstances. In some cases, the element or component can bealtered, changed, or modified to a new position, state, and/or conditionas a result of adjustment, if appropriate or desired.

In addition, certain terminology may also be used in the followingdescription for the purpose of reference only, and thus are not intendedto be limiting. For example, terms such as “first”, “second”, and othersuch numerical terms referring to structures do not imply a sequence ororder unless clearly indicated by the context.

For the sake of brevity, the connecting lines shown in the variousfigures contained herein are intended to represent exemplary functionalrelationships and/or physical couplings between the various elements. Itshould be noted that many alternative or additional functionalrelationships or physical connections may be present in an embodiment ofthe subject matter.

FIG. 1 is a schematic of an embodiment of a vehicle 100 comprising anadaptive cruise control system (ACCS) 110. The vehicle 100 furthercomprises an engine control module (ECM) 120 coupled to the ACCS 110.The ECM 120 is preferably coupled to a power device 122. Various otherinput and output systems can be coupled to the ECM 120, including, amongothers, an accelerator pedal sensor 130 coupled to an accelerator pedal132, a resume control 140 coupled to the ECM 120, and a transmissionoutput shaft sensor (TOSS) 150 coupled to the transmission output shaft152 of the vehicle 100. The ACCS 110 can also be coupled to arange-finding system 160 and a wheel speed sensor 170, the wheel speedsensor 170 coupled to a wheel 172 of the vehicle 100. Certain operationsof the ACCS 110 can require input from multiple sources or validation bymultiple components prior to execution. The use of multiple sourcesinsures against executing operations in response to transient or errantsignals received by the ACCS 110, extending its safe operation intopreviously challenging situations, as described below.

Although certain components are described as coupled, they are notexclusively coupled in all embodiments. For example, although theaccelerator pedal sensor 130 is described and illustrated as coupled tothe ECM 120, in other embodiments, the accelerator pedal sensor 130 canbe coupled to the ACCS 110 as well. Such connections and/or couplingsare omitted for clarity, and do not suggest that additional couplingsand/or operational features are not contemplated. Rather, theaccelerator pedal sensor 130 can, in some embodiments, be coupled to theACCS 110 in addition to, or instead of, the ECM 120, and can providesignals to any coupled component, as appropriate for the embodiment.

The ACCS 110 is preferably an electronic component capable of performingfunctions typical of adaptive cruise control systems. The ACCS 110 issimilar to traditional vehicular cruise control systems in somerespects, such as the capability of maintaining the vehicle 100 at arelatively constant speed without operator input through the acceleratorpedal 132. Additionally, through manipulation of certain input devices,the ACCS 110 can decrease or increase the cruising speed of the vehicle100 without disengaging. The ACCS 110 can be engaged in response toreceiving an engagement signal from an operator input device, such as abutton or switch. The ACCS 110 can be disengaged after receiving acancel or disengagement signal. Such signals can originate at any ofvarious sources, such as a brake pedal of the vehicle 100, or a cancelbutton, part of the collection of input devices. The ECM 120 canadditionally transmit signals to the ACCS 110 resulting in disengagementof the ACCS 110. Some of the operational features of the ACCS 110 arefurther described below.

The ACCS 110 is preferably controlled by the operator of the vehicle 100through a collection of input devices, such as buttons, switches, orlevers presented near other control input devices. In certainembodiments, the input devices can be integrated into other devices.Thus, a lever with one function of engaging or disengaging turn signalsor blinkers on the vehicle 100 can additionally have a button or switchthrough which the ACCS 110 can be commanded. In certain embodiments, theinterface devices through which the operator commands the ACCS 110 canbe enabled or disabled through a master control switch.

One such operator input device is the resume control 140. The resumecontrol 140 can be embodied by any of a variety of operator inputmechanisms or devices employed as part of an ACCS interface assembly orcruise control command interface. Accordingly, the resume control 140can be one of many cruise control command buttons, or any element of theassembly or interface. Such an assembly can include any desired numberof buttons, switches, knobs, touch pads, soft-button controls, voiceresponse devices, or other input devices.

Accordingly, the resume control 140 can be a single button, or combinedwith other functions on a single input device. When combined, thefunction performed by the ACCS 110 in response to operator manipulationcan be based on the operational state of the ACCS 110 when the input isreceived. As one non-limiting example, a “resume” function can becombined with a function indicating “acceleration” and labeled“Resume/Accel” in some ACCS embodiments. When such a button is pressed,if the ACCS 110 is currently disengaged, it can attempt to re-engagecontrol of the power device 122. Additionally, if the ACCS 110 isalready engaged, the ACCS 110 can instead provide a command signal tothe ECM 120 indicating a speed increase to a new cruising speed shouldbe executed.

In certain embodiments, multiple buttons can be used, requiringsimultaneous, substantially simultaneous, or sequential manipulation toresult in the functional equivalent of the described resume control 140.In certain embodiments, the resume control 140 can be a single button orswitch, but only perform the described functions in response to apattern or sequence of manipulation, to prevent inadvertent activation.Therefore, although the resume control 140 is described in an isolatedcontext with regard to certain functions of the embodiment of thevehicle 100, in other embodiments, the operative features of the resumecontrol 140 can be embodied in different interface features.

The ECM 120 can be any type of electronic controller used in“drive-by-wire” equipped vehicles to receive input signals from theoperator of the vehicle 100 and to command the power device 122 inresponse. For example, the accelerator pedal 132 can be an electronicinput device without hydraulic or mechanical connection or coupling tothe power device 122. Instead, the accelerator pedal sensor 130 candetect the position of the accelerator pedal 132 and the ECM 120 canoperate the power device 122 in response. The ECM 120 can additionallyreceive information via signals from other sensors and input devices,including the TOSS 150, as appropriate.

The ECM 120 preferably operates the power device 122 in response tosignals from the ACCS 110. Thus, where the ACCS 110 transmits a speedreduction or increase signal, the ECM 120 receives the signal and, asfurther described below, operates the power device 122 in response,decreasing or increasing the speed of the vehicle 100 as appropriate.

The ECM 120 can perform some or all of the described operations itself,or can cooperate with another controller of the vehicle 100. Forexample, the ECM 120 can receive sensor data directly, or in certainembodiments, a separate controller component can receive the sensor dataand relay it to the ECM 120. Thus, while some computation and evaluationfunctions are described as being performed by the ECM 120, they also canbe performed by a separate component, and the results provided to theECM 120 for action to be taken, depending on the results. Accordingly,while computation and comparison steps or methods may be described inrelation to the ECM 120, the ECM 120 can, in various embodiments,perform all, some, or none of the steps, while still performingoperations in response to the computations or comparisons produced.

Additionally, the ECM 120 can be comprised of one or moreprocessor-based devices, which may be physically integrated into asingle component or circuit board. In certain embodiments, the ECM 120can be distributed throughout the electronic and/or computingarchitecture of the vehicle 100, including integration with componentsperforming additional functions.

The power device 122 is any type of power generating source sufficientto move the vehicle 100. Although described in the context of aninternal combustion engine for an automobile, the system and techniquesdescribed herein can apply to other types of vehicles, including thoseemploying different engine types. Some examples can include internalcombustion engines, hybrid engines, an electric motor, a fuel cell, andso on. Thus, the power device 122 is not limited to vehicles withengines, but embodiments can include any type of vehicle with such acomponent providing the moving force.

The accelerator pedal 132 is preferably a pedal of any type suitable topermit the operator of the vehicle 100 to provide signals to the ECM 120indicating a desired increase in speed of the vehicle 100. Accordingly,the accelerator pedal 132 can be of any type known in the art, and isdescribed with regard to its functional features, and is not tied to aspecific physical embodiment.

The accelerator pedal sensor 130 is preferably coupled to theaccelerator pedal 132 for the purpose of detecting input from theoperator via manipulation of the accelerator pedal 132. Thus, theaccelerator pedal sensor 130 can detect pressure applied to theaccelerator pedal 132, as well as the position of the accelerator pedal132 and its rate of travel, any or all of which can be used to determinethe appropriate response to the operator's manipulation. For example,the accelerator pedal sensor 130 can detect the position of theaccelerator pedal 132 for purposes of determining the level ofacceleration of the vehicle desired by the operator. Alternatively oradditionally, the accelerator pedal sensor 130 can detect the rate ofengagement of the accelerator pedal 132, which can be used to determinewhether the operator desires a rapid or slow acceleration in response.

Thus, the accelerator pedal sensor 130 can be of any suitable type toperform the described operations, including multiple sensors whereappropriate. Thus, a potentiometer, strain gauge, piezoelectriccomponent, or any other type of sensor can be used as desired for theembodiment. Preferably, however, the type of sensor provides theinformation required for the ECM 120 to command the power device 122responsively to the input. Signals from the accelerator pedal sensor 130can be received by the ECM 120 for use in controlling the power device122.

Where sensors are described, they are described functionally. The inputobject from which the quantity being measured is received is useddescriptively in the name, and should be understood that thisinformation is derived from signals generated by the sensor in responseto its detecting functions, regardless of where they are processed todetermine the detected quantity. A rotation sensor, for example, will bedescribed for exemplary purposes. The rotation sensor can generate avoltage which varies according to the rotational rate of the inspectedobject. In some embodiments, the rotation sensor can provide the voltageto another system, such as the ECM 120, which will perform operations todetermine the acceleration to which the voltage level corresponds. Inother embodiments, the rotation sensor can perform the operationsinternally. In such embodiments, the rotation sensor will provide asignal indicating the rotational rate directly, instead of the voltagelevel. In certain embodiments, the rotation sensor can provide both thesignal indicating rotational rate, as well as the voltage to othercomponents. Thus, for sensors described throughout, the sensor canperform in any of these modes, as appropriate and/or desired for theembodiment.

The TOSS 150 is any sensor coupled to the transmission output shaft 152.The TOSS 150 is preferably capable of detecting the rotation rate of thetransmission output shaft 152. From the information received from theTOSS 150, the ECM 120 can determine the speed of the vehicle 100. Othertechniques for determining vehicle speed can also be used. The TOSS 150can function by providing a voltage to the ECM 120 or by providing asignal indicating either the rotational rate of the transmission outputshaft 152 or the speed of the vehicle 100 corresponding to the detectedrotational rate, if configured for the embodiment. Other detection andreporting types are possible, as described above.

Similarly, the wheel speed sensor 170 can monitor the rotational rate ofa wheel 172 of the vehicle 100. The wheel speed sensor 170 can transmita signal indicating the rotational rate of the wheel 172, or wheelspeed, or, in certain embodiments, provide the speed of the vehicle 100as determined based upon the wheel speed. Thus, the wheel speed sensor170 can be of any type described previously, and preferably performs thedescribed functions, although the physical embodiment can vary betweenembodiments of the vehicle 100. In the illustrated embodiment, the wheelspeed sensor 170 is coupled to the ACCS 110. In other embodiments, thewheel speed sensor 170 can be coupled to additional components, such asthe ECM 120, as described above.

The range-finding system 160 is any remote detection system used by thevehicle 100 to monitor the surrounding environment. Thus, therange-finding system 160 can be a RADAR system, a LIDAR system, anear-field sensing system, a camera and video-recognition system, or anyother type capable of performing the functions described.

Preferably, the range-finding system 160 can detect objects in front ofthe vehicle 100. Certain embodiments of the range-finding system 160 candetect objects to the sides and rear as well. Accordingly, althoughillustrated as a single component, the range-finding system 160 cansometimes comprises a variety of sub-components distributed throughoutthe vehicle 100 to perform the described functions.

In addition to detecting the presence of an object, the range-findingsystem 160 can preferably determine the speed of the object, eitherobjectively or relative to the vehicle 100. Preferably the range-findingsystem 160 also can determine the distance between the vehicle 100 andthe object. Together with the speed of the object relative to thevehicle 100, the system can then determine a time gap between thevehicle 100 and the object. The time gap is the amount of time betweenthe rear of a travelling object ahead of the vehicle 100 and the frontof the vehicle 100. Thus, a time gap of five seconds indicates that ifthe travelling object were to pass a particular position on the road,five seconds after the rear of the object 200 was at the position, thefront of the vehicle 100 would reach the position. Additionaldescription of operation of the ACCS 110 is provided with reference toFIGS. 2 and 3 below.

Certain embodiments of the range-finding system 160 can perform bothsensing and calculation operations internally, while others can provideinformation and readings to other components of the vehicle 100,including the ACCS 110. In such embodiments, the ACCS 110, or othercomponent(s) can perform operations to determine the time gap and otheraspects of ranging information independently.

The ACCS 110 can be configured to monitor travel behind the precedingvehicle 200 either at a set distance or at a set time gap. Accordingly,information from the range-finding system 160 is preferably provided tothe ACCS 110. In response, the ACCS 110 can transmit signals to the ECM120, resulting in adjustment of the operation of the power device 122 torespond to changes in the driving environment caused by other vehicles,among other things.

Distance- or time-following are features of the ACCS 110 in addition totraditional cruise control system features. Through the use of suchfeatures, the vehicle 100 can be safely operated under changing drivingconditions, unlike traditional systems. Examples of operation of theACCS 110 are made with reference to FIGS. 2 and 3.

As shown in FIG. 2, the ACCS 110 can receive information from therange-finding system 160 indicating a preceding vehicle 200 istravelling in front of the vehicle 100. The preceding vehicle 200 may betravelling at a slower speed than the vehicle 100, resulting in thevehicle 100 approaching the preceding vehicle 200. While the vehicle 100is operating at a cruising speed, the range-finding system 160 cantransmit a wireless signal 162 periodically or continuously. With thewireless signal 162, the range-finding system 160 can detect thepresence of the preceding vehicle 200, its distance from the front ofthe vehicle 100, and its speed and provide this information to the ACCS110 as an alert signal. The alert signal can include information such asthe fact of the existence of the preceding vehicle 200, its distancefrom the front of the vehicle 100, and its speed, and any other desiredinformation, as described below. The range-finding system 160 can beconfigured to ignore objects beyond a certain distance or proximitythreshold. The range-finding system 160 can be further configured toonly transmit alert signals to the ACCS 110 for objects within theproximity threshold.

The ACCS 110 can reduce the speed of the vehicle 100 to prevent closelyapproaching the preceding vehicle 200. The ACCS 110 preferably transmitsa speed decrease signal to the ECM 120, which can reduce the speed ofthe vehicle 100 through operation of the power device 122. Preferably,the speed of the vehicle 100 is adjusted to match or nearly match thatof the preceding vehicle 200 while following at a safe distance. Thefollowing distance can be preconfigured or determined at a set time gap.The time gap specified can differ for different speeds, and the ACCS 110can use different following techniques at different speeds. For example,a time gap of three seconds may be used for following the precedingvehicle 200 at 65 miles per hour, while a time gap of one second is usedfor following the preceding vehicle 200 at twenty miles per hour. Incertain embodiments, the time gap can be constant, if desired. In someembodiments, the ACCS 110 can maintain a constant distance between thevehicle 100 and the preceding vehicle 200 at low speeds, while using atime gap following technique at higher speeds. Other embodiments can usedifferent combinations of time gap and distance following techniques.The exact combination and/or parameters can be configured for eachembodiment of the ACCS 110 as desired.

As shown in FIG. 3, the ACCS 110 can be configured to bring the vehicle100 to a stop behind a stopped vehicle 300. The range-finding system 160can transmit the wireless signal 162 to determine the speed and distanceof the stopped vehicle 300. In this example, the stopped vehicle 300 hasa speed of zero miles per hour. Accordingly, the ACCS 110 can reduce thevehicle 100 to a stop as well, at a preconfigured distance behind thestopped vehicle 300. The range-finding system 160 can be used to monitorthe distance between the front of the vehicle 100 and the rear of thestopped vehicle 300. The ACCS 110 can act on the alert signal from therange-finding system 160 to properly stop the vehicle 100 at the desireddistance. Certain embodiments of the ACCS 110 can operate one or morebraking system of the vehicle 100 to decrease the speed of the vehicle100, in addition to any speed reduction caused by adjusting theoperation of the power device 122.

The ACCS 110 can be configured to resume travel from such a stop. Toresume travel at the appropriate time, however, operator input isrequired. With reference to FIG. 3, it would be inappropriate for theACCS 110 to resume travel behind the stopped vehicle 300 when thestopped vehicle 300 increased speed. If such a simple instruction setwere used, the vehicle 100 would travel through the stop sign 302without stopping when the stopped vehicle 300 moved forward. Thisundesirable result can be avoided by resuming travel of the vehicle 100only in response to operator input. FIG. 4 illustrates the steps of amethod for operating a vehicle using an ACCS with such operator input.

The various tasks performed in connection with method 400 may beperformed by software, hardware, firmware, or any combination thereof.For illustrative purposes, the following description of method 400 mayrefer to elements mentioned above in connection with FIGS. 1-3. Inpractice, portions of method 400 may be performed by different elementsof the described system, e.g., ACCS 110, ECM 120, power device 122,resume control 140, among others. It should be appreciated that method400 may include any number of additional or alternative tasks, the tasksshown in FIG. 4 need not be performed in the illustrated order, andmethod 400 may be incorporated into a more comprehensive procedure orprocess having additional functionality not described in detail herein.

Operation of the ACCS 110 begins when the ACCS 110 receives an engagesignal from the operator (task 402). In response, the ACCS 110 canbecome engaged (task 404), operating certain aspects of control of thevehicle 100, such as speed control. As with traditional cruise controlsystems, steering can remain under control of the operator. The ACCS 110can be disengaged at any time through the techniques described above.During operation, the ACCS 110 can make use of information from therange-finding system 160 to monitor the space in front of the vehicle100 for obstacles. When the ACCS 110 detects the presence of such anobstacle (task 406), it can transmit a speed decrease signal to the ECM120. In response, the ECM 120 can reduce the speed of the vehicle (task408). Under certain circumstances, this can be sufficient, and, asdescribed above, the ACCS 110 can maintain a following distance behindthe obstacle at the reduced speed. The range-finding system 160 can beused to monitor the distance and respond accordingly.

In some situations, however, the ACCS 110 will bring the vehicle 100 toa stop (task 410), such as behind the stopped vehicle 300. Prior to anyother actions, including operator-initiated resumption of travel, thatthe travel of the vehicle 100 has been halted can be verified by twoseparate components (task 412). A first sensor, such as the wheel speedsensor 170 can provide speed information via a signal to the ACCS 110.Similarly, a second sensor, such as the TOSS 150, can provide speedinformation via a signal to the ECM 120. Other sensors coupled to eitherthe ACCS 110 and/or ECM 120 can be used as well.

The ACCS 110 can exchange signals with the ECM 120, unilaterally receivea signal from the ECM 120, or unilaterally transmit a signal to the ECM120 indicating the vehicle's speed as determined from the firstsensor—here, the wheel speed sensor 170. The ECM 120 can transmit asignal to the ACCS 110 including the speed information obtained from thesecond sensor and/or receive information from the ACCS 110.Subsequently, the ECM 120 can compare the information received from theACCS 110 with its own information to determine if both sensorsindependently provide information indicating the vehicle is stopped(task 414).

In the event that the two sensors each report a different speed for thevehicle 100, the ACCS 110 can be disengaged 415, returning the vehicle100 to operator manual control. Small variations of measurement of speedbetween the sensors can be permitted, and configurable to theembodiment. For example, if the first sensor indicates the vehicle'sspeed at 0.0 miles per hour, while the second sensor indicates thevehicle's speed at 0.2 miles per hour, the information can be consideredas the same by the ECM 120 if configured to permit at least 0.2 milesper hour variation between the readings. Nonetheless, where thevehicle's speed is not verified by two sensors within the preconfiguredtolerance, the ACCS 110 is preferably disengaged (task 415).

If the two sensors verify that the vehicle is stopped, to resume travelunder ACCS 110 operation, the operator must supply a resume signal.Preferably, the resume signal is verified by two components, includingthe ACCS 110 and ECM 120. In this way, the ACCS 110 will notinappropriately resume travel of the vehicle 100, and a single errant oranomalous signal will not be received as a valid resume signal.

Thus, a resume signal can be detected (task 416), such as manipulationof the resume control 140. A resume signal can originate at othersources, as well, if desired. One such example is detection ofengagement of the accelerator pedal 132 by the accelerator pedal sensor130. Other sources can be used, as described above. The resume signal ispreferably received by the ECM 120 and ACCS 110. In certain embodiments,the resume control 140 can be coupled to both the ACCS 110 and ECM 120.In such embodiments, the signal can be received by the ACCS 110directly. In some embodiments, however, the resume signal can bereceived solely by the ECM 120. In such embodiments, the ECM 120 canrelay the resume signal as a relayed resume signal to the ACCS 110.

When a resume signal is received (task 416), the ACCS 110 and ECM 120must both receive the resume signal prior to the ACCS 110 resumingoperation (task 418). Thus, where the ACCS 110 alone receives a resumesignal, it can respond by transmitting signals to the ECM 120 to resumetravel, as described in greater detail below. The ECM 120 will notexecute adjustments to the power device 122, including speed increases,based on signals from the ACCS 110 because it has not also received aresume signal. In such situations, the ACCS 110 can be disengaged (task420) and manual control returned to the operator.

In certain embodiments, the ECM 120 can recognize a timed window inwhich to receive a resume signal after receiving signals from the ACCS110 to resume acceleration. For example, where the ACCS 110 receives afirst resume signal that, for whatever reason, is not simultaneouslyprovided to the ECM 120, the ACCS 110 can send an acceleration signal tothe ECM 120. Because the ECM 120 has not received the first resumesignal also, it will not immediately begin acceleration. In someembodiments, however, the ECM 120 can monitor for a second resume signalwithin a preconfigured period of time. If the ECM 120 receives a secondresume signal within the period of time, it can operate the power device122 to accelerate. In this way, the operator can initiate resume signalsmore than once to resume travel without having to re-engage the ACCS 110in the event one component fails to receive the first resume signal.

In those embodiments where the ECM 120 provides a relayed resume signal,signals from the ACCS 110 will be executed because the ECM 120 receivedthe resume signal. In those embodiments where the resume signal isreceived by both the ACCS 110 and ECM 120, the ECM 120 will executeadjustments to the power device 122 in response to signals from the ACCS110 because the ECM 120 previously received the resume signal. Multiplesequential stops and resumption of travel of the vehicle 100 can be thusexecuted, where the ACCS 110 and ECM 120 perform each set of steps aftereach stop of the vehicle.

In this way, the ECM 120 will not increase the speed of the vehicle 100from a stopped position unless both the ACCS 110 and ECM 120 receive aresume signal or relayed resume signal. In the event that the resumesignal is detected by both components (step 422), the vehicle 100 willstill not resume travel unless the obstacle which caused the stop hasmoved. Thus, the ACCS 110 can rely on information from the range-findingsystem 160 to determine whether the obstacle is still stopped in frontof the vehicle 100 (task 424). When the obstacle is still stopped, butthe resume signal has been verified by two components, the ACCS 110 canwait until the obstacle has moved to resume travel. If the obstacle hasmoved, travel of the vehicle 100 can resume immediately (task 426).Subsequent to resuming travel, the ACCS 110 can continue to monitor thespace in front of the vehicle 100 with the range-finding system 160 forobstacles and potential speed adjustments.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or embodiments described herein are not intended tolimit the scope, applicability, or configuration of the claimed subjectmatter in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing the described embodiment or embodiments. It should beunderstood that various changes can be made in the function andarrangement of elements without departing from the scope defined by theclaims, which includes known equivalents and foreseeable equivalents atthe time of filing this patent application.

1. A method of operating a vehicle comprising an adaptive cruise controlsystem and an engine control module coupled to the adaptive cruisecontrol system, the method comprising: issuing a speed reduction signalfrom the adaptive cruise control system; verifying a speed reductionwith a first sensor using the adaptive cruise control system; verifyingthe speed reduction with a second sensor using the engine controlmodule; thereafter, receiving a resume signal from an operator inputdevice; and executing a speed increase of the vehicle with the enginecontrol module in response to receiving the resume signal with theengine control module.
 2. The method of claim 1, wherein executing thespeed reduction of the vehicle comprises stopping the vehicle.
 3. Themethod of claim 1, wherein verifying the speed reduction with the firstsensor comprises receiving a wheel speed signal from a wheel sensor withthe adaptive cruise control system.
 4. The method of claim 1, whereinverifying the speed reduction with the second sensor comprises receivinga transmission shaft speed signal from a transmission output shaftsensor with the engine control module.
 5. The method of claim 1, whereinreceiving the resume signal from the operator input device comprisesreceiving the resume signal from an accelerator pedal sensor.
 6. Themethod of claim 1, wherein receiving the resume signal from the operatorinput device comprises receiving the resume signal from a cruise controlcommand button.
 7. The method of claim 1, further comprising:transmitting a speed increase signal from the adaptive cruise controlsystem to the engine control module in response to receiving the resumesignal with the adaptive cruise control system; and wherein executingthe speed increase comprises moving the vehicle from a stopped positionwith the engine control module in response to receiving the resumesignal and the speed increase signal with the engine control module. 8.The method of claim 7, wherein receiving the resume signal comprisesreceiving the resume signal with the adaptive cruise control system andthe engine control module.
 9. A method of operating a vehicle comprisingan adaptive cruise control system and an engine control module coupledto the adaptive cruise control system, the method comprising: receivinga resume signal at the engine control module; the engine control modulerelaying the resume signal as a relayed resume signal to the adaptivecruise control system; receiving a speed increase signal at the enginecontrol module; and executing a speed increase of the vehicle with theengine control module in response to the resume signal and the speedincrease signal.
 10. The method of claim 9, wherein receiving the resumesignal comprises receiving a signal from a cruise control commandbutton.
 11. The method of claim 9, wherein receiving the resume signalcomprises receiving a signal from an accelerator pedal sensor.
 12. Themethod of claim 9, further comprising: issuing a speed reduction commandfrom the adaptive cruise control system; verifying a speed reduction ofthe vehicle using a first sensor coupled to the adaptive cruise controlsystem and a second sensor coupled to the engine control module.
 13. Themethod of claim 12, wherein verifying the speed reduction using thefirst sensor comprises receiving a speed signal from a wheel speedsensor coupled to the adaptive cruise control system.
 14. The method ofclaim 12, wherein verifying the speed reduction using the second sensorcomprises receiving a shaft speed signal from a transmission outputshaft sensor coupled to the engine control module.
 15. The method ofclaim 12, wherein the vehicle further comprises a range-finding systemcoupled to the adaptive cruise control system, and the method furthercomprises: detecting an obstacle in the path of the vehicle;transmitting an alert signal with the range-finding system in responseto detecting the obstacle; and issuing the speed reduction command inresponse to receiving the alert signal from the range-finding system.16. A vehicular control system for a vehicle, the system comprising: anadaptive cruise control system adapted to: engage an adaptive cruisecontrol mode in response to receiving an engagement signal from anoperator of the vehicle; transmit a speed reduction signal during theadaptive cruise control mode; verify speed reduction of the vehicleusing a first sensor, the speed reduction of the vehicle beinginfluenced by the speed reduction signal; receive a resume signal fromthe operator during the adaptive cruise control mode; and transmit aspeed increase signal in response to receiving the resume signal; and anengine control module coupled to the adaptive cruise control system andadapted to: receive the speed reduction signal; execute the speedreduction in response to receiving the speed reduction signal; verifythe speed reduction using a second sensor; receive the resume signal;and execute a speed increase of the engine in response to receiving theresume signal and the speed increase signal.
 17. The vehicular enginecontrol system of claim 16, wherein the first sensor comprises a wheelspeed sensor.
 18. The vehicular engine control system of claim 16,further comprising a range-finding system adapted to determine afollowing distance between the vehicle and a preceding vehicle and totransmit an alert signal in response to detecting a following distancebelow a proximity threshold.
 19. The vehicular engine control system ofclaim 18, wherein the adaptive cruise control system is further adaptedto transmit the speed reduction signal in response to receiving thealert signal.
 20. The vehicular engine control system of claim 16,further comprising a resume button adapted to transmit the resume signalin response to manipulation by the operator.